a. Field of the Invention
The present disclosure relates to catheters and other maneuverable medical devices. More specifically, the present disclosure relates to a multi-direction control handle for steerable catheters and other maneuverable medical devices.
b. Background Art
Catheters (i.e., catheters or sheaths) that have flexible tubular bodies with deflectable distal ends and control handles for controlling distal end deflection are used for many noninvasive medical procedures. For example, catheters having conductive electrodes along the distal ends of their bodies are commonly used for intra-cardiac electrophysiology studies. The distal end of a catheter body is typically placed into a patient's heart to monitor and/or record the intra-cardiac electrical signals during electrophysiology studies or during intra-cardiac mapping. The orientation or configuration of the distal end is controlled via an actuator located on the catheter's control handle, which remains outside the patient's body. The electrodes conduct cardiac electrical signals to appropriate monitoring and recording devices that are operatively connected at the control handle.
Typically, a catheter body is cylindrical and electrically non-conductive. The catheter body includes a flexible tube constructed from polyurethane, nylon or other electrically non-conductive flexible material. The catheter body further includes braided steel wires or other non-metallic fibers in its wall as reinforcing elements. Each electrode has a relatively fine electrically conductive wire attached thereto and extending through the catheter body. The conductive wire extends from the distal end to a proximal end where electrical connectors such as plugs or jacks are provided to be plugged into a corresponding socket provided in a recording or monitoring device.
The distal portion of the catheter body is selectively deformed into a variety of curved configurations using the actuator on the control handle. The actuator is commonly internally linked to the distal portion of the catheter body by at least one deflection wire. Some catheter bodies employ a single deflection wire, which is pulled (i.e., placed in tension) by the actuator in order to cause the distal portion of the catheter body to deform. Other catheter bodies have at least two deflection wires, where the displacement of one wire (i.e., placing one wire in tension) results in the other wire going slack (i.e., the wire does not carry a compressive load). In such catheters, where the deflection wires are not adapted to carry compressive loads (i.e., the deflection wires are only meant to be placed in tension), the deflection wires are commonly called pull or tension wires.
To deform the distal end of the catheter body into a variety of configurations, a more recent catheter design employs a pair of deflection wires that are adapted such that one of the deflection wires carries a compressive force when the other deflection wire carries a tensile force. In such catheters, where the deflection wires are adapted to carry both compressive and tension loads, the deflection wires are commonly called push/pull or tension/compression wires and the corresponding catheter actuators are called push-pull actuators.
Prior art control handles for controlling distal end deflection of catheter bodies have several drawbacks that adversely impact the handles' ability to be operated. First, the control handles are often excessively bulky. Second, the control handles are often inadequate with respect to their ability to provide finely controlled deflection adjustment for the distal end of the catheter body. Third, the control handles often provide inadequate deflection wire travel for a desired medical procedure. Fourth, the control handles often have a mechanical advantage that is less than desirable and, as a result, require significant effort to operate on the part of a user. Fifth, once a desired body distal end deflection has been reached, the control handles typically require the physician to take a conscious step to maintain the catheter at the desired deflection. Sixth, the wire displacement mechanisms within the control handles have a tendency to permanently deform the deflection wires. Seventh, the wire displacement mechanisms within the control handles typically make it difficult, if not impossible, to provide a lumen that runs uninterrupted from the proximal end of the control handle to the distal end of the catheter body.
There is therefore a need for a catheter that minimizes or eliminates one or more of the problems set forth above.